Downward-draft furnace



(No Model.)

J. F. BLISS. DOWNWARD DR'APT FURNACE.

Patented July 26, 1892.

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UNITED STATES PATENT OFFICE.

JAMES F. BLISS, OF BOSTON, MASSACHUSETTS.

DOWNWARD-DRAFT FURNACE.

SPECIFICATION forming part of Letters Patent No. 479,697, dated July 26, 1892.

Application filed October 31. 1889. Serial No. 328.825. (No model.)

To all whom it may concern.-

Be it known that I, JAMES F. BLISS, of Boston, in the county of Suffolk and State of Massachusetts have invented certain new and useful Improvements in Downward Draft Furnaces, of which the following, taken in connection with the accompanying drawings, is a specification.

The object of my invention is to utilize for various mechanical, chemical or metallurgical purposes the exceedingly-hot flame-current produced by the combustion of gases in the fiame-ohamber of a downward-draft furnace. Examples of such furnaces are shown in the Post and Sawyer patents of June 3, 1884, No. 299,578, October 19, 1886, No. 351,338, October 26, 1886, No. 351,652, and December 4, 1888, No. 3%,131, in which a water-grate supports the coal or other solid fuel and waterwalls resist the extreme heat in the chamber below the grate, the draft being downward and the evolved gases being caused to pass downwardly through the fire and to be consumed in the said chamber to more speedily convert into steam the water in the grate-tubes and inclosing walls. By my improvements the excess of heat in the interior of such chamber is utilized for purposes other than steam-making by introducing into the chamber materials to be heated ormelted by the direct action of the flame-currents, so that the apparatus becomes at the same time a generator of steam and a furnace for heating or melting materials which may be furthertreated in machines driven by the power so generated or otherwise.

Thus iron rods or bars may be heated to a red or White heat and removed from said chamber for conversion into nails, horseshoes, or other mechanical forms, provision being made for insertion and removal without material interruption of the downward current.

In carrying out my invention I provide certain means for introducing and removing the articles to be subjected to the action of the flame, such as water-containing tracks or slides, horizontal or inclined, in the lower part of the flame-chamber for the support and movement of the crucibles, bars, or materials under treatment, and also doors or openings of peculiar construction adapted to close around or laterally against an article being introduced or removed, so as to limit the entrance of air below the grate. I also provide one or more transparent panels through which the interior of the closed furnace may be viewed. Ores to be treated may be introduced in fire-proof crucibles fitting upon the tubular tracks through which a current of water flows or placed in inclined troughs similarly protected.

The drawings represent, in Figures 1 and 2,

longitudinal and transverse vertical sections of a suitable form of downward-draft furnace fitted with some of the devices appropriate to and forming part of my invention. I do not, however, claim as original with me the general form of furnace shown; nor do I limit myself to that specific form, as I utilize any downdraft furnace having a flame-chamber below the grate, into and through which the descending flame-current passes to act upon materials introduced into the chamber, as stated. Fig. 3 represents a door adapted forintroduction of the bars or crucibles, and Fig. 4 is a detail. A is the outer shell of the furnace, and B the inner shell or fire-pot, represented as square in cross-section, to give abundant space in the flame-chamber 0 below the tubular grate D and circulating-pipes E.

F is a depending water-leg connecting with the water-walls G and supplying water for circulation through the tubes E D and water-box H, as described in the Post and Sawyer patent of December 4:, 1888.

I represents the open draft and feed door.

J J represent water-tubes, one or more, laid on or near the bottom B of the flame-chamber, serving as a feed-water inlet, and forming tracks, ways, or guides for convenient insertion and removal of materials placed in open or closed retorts or crucibles K, introduced into the chamber 0. By admitting the feedwater through the tracks J they are kept from warping or melting, which would occur under the intense heat if not thus protected. They are shown as extending outside of the chamher, so that the crucibles may be supported and readily inserted and removed.

One or more suitable doors L are provided having a sliding or swinging movement to open and close the chamber-entrance. The

form shown in Figs. 1 and 3 is hinged at top and recessed at bottom to fit around the tracks J. These figures also show an opening through slides may close laterally against the sides of the rod or bar and have a swinging plate to cover the hole when not being used, as illustrated in Fig. 4. A transparent panel P is furnished, of suitable dimensions to afford aview of the articles introduced into the chamber.

I claim as my invention 1. A furnace having above its grate a draft and feed inlet and below the grate a flamechamber, as described, in combination with longitudinal Water-containin g tracks through the lower part of said chamber and a door for insertion and removal of articles to be moved along such tracks, substantially as set forth.

2. In a downdraft-furnace, the combination, with the flame-chamber below the grate, of tracks or supports within such chamber, a door in line therewith for inserting and removing articles to be heated, and a transparent panel for inspection of the interior of such chamber, substantially as set forth.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses, on this 19th day of October, A. D. 1889.

JAMES F. BLISS.

Witnesses:

A. H. SPENCER, J AMES P. PRINCE. 

